Early detection photo controls

ABSTRACT

A conveyor system includes a diverter positioned between an upstream conveyor and several downstream conveyors and splits or switches a procession of objects conveyed by the upstream conveyor to one of the downstream conveyors where the downstream conveyors are provided with a plurality of sensors along their lengths that detect the presence or absence of objects on the downstream conveyors at different positions along their lengths and supply signals to the diverter to control the diverter to switch between the downstream conveyors to direct the objects conveyed by the upstream conveyor to the one of the downstream conveyors having fewer objects being conveyed by the conveyor and also controls the number of objects delivered by the diverter to the downstream conveyors.

This application is a continuation-in-part of patent application Ser.No. 09/590,894 filed Jun. 9, 2000 and now U.S. Pat. No. 6,347,697, andof patent application Ser. No. 09/723,579 filed Nov. 28, 2000 andcurrently pending.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention pertains to a conveyor system comprising at leastone upstream or infeed conveyor that conveys objects to a pair ofdownstream conveyors. More specifically, the conveyor system includes adiverter positioned between the upstream conveyor and first and seconddownstream conveyors that splits or switches a procession of objectsconveyed by the upstream conveyor to one of the two downstreamconveyors. The upstream or infeed conveyor includes improvements thatenable it to monitor the number of objects being conveyed by theconveyor to the diverter and to monitor any spacings occurring betweenthe number of objects to ensure that a predetermined number of objectswill remain on the conveyor before the diverter when the gates of thediverter are closed where the number of objects accumulated on theconveyor when the gates are closed will act as a cushion for additionalobjects being conveyed on the upstream conveyor to impact with andprevent those additional objects from falling over. In addition, theupstream conveyor includes improvements that avoid the falling over ofobjects as the gate of the diverter is opened to direct a procession ofobjects held back by the diverter gate to one of the first and seconddownstream conveyors.

(2) Description of the Related Art

A typical split path conveyor system employs at least one upstream orinfeed conveyor and at least two downstream conveyor lanes with adiverter positioned between the upstream conveyor and the downstreamconveyor lanes. The diverter selectively directs a procession of objectsconveyed by the upstream conveyor to one of the two downstream conveyorlanes. Split path conveyor systems of this type are typically used inconveyor systems that load a plurality of objects onto a rectangularpallet. The conveyor system will employ an upstream conveyor thatsupplies a procession of objects to the two lanes of the downstreamconveyor through a diverter that directs the objects to one of the twolanes of the downstream conveyor, and then could also employ twoadditional pairs of further downstream conveyor lanes that are suppliedwith the procession of objects from the pair of downstream conveyorlanes by a pair of diverters. The number of times the path of conveyedobjects is split is usually determined by the number of rows of objectsthat are ultimately directed to the pallet being loaded with theobjects. For example, if the pallet is loaded with four rows of objects,then the upstream conveyor will be split through a diverter to a pair ofdownstream conveyor lanes, and then each of the downstream conveyorlanes of the pair will be split by an additional pair of diverters totwo pairs of further downstream conveyor lanes, resulting in fourconveyor lanes conveying four rows of objects to the pallet beingloaded.

In a belt conveyor slit path conveying system, the upstream conveyortypically comprises a belt conveyor that conveys objects in uprightorientations in single file between pairs of guide rails that arepositioned above the belt conveyor and extend the length of the beltconveyor. The upstream conveyor conveys the procession of objectsbetween the guide rails to a diverter that selectively directs theprocession of objects received from the upstream conveyor to one of atleast two downstream conveyor lanes. Like the upstream conveyors, thedownstream conveyor lanes, for example a first and second downstreamconveyor lane, will continue to convey the objects in their uprightorientations between a pair of guide rails positioned above a conveyorbelt and extending along the length of the conveyor belt. In prior artsplit path belt conveyors, the pair of downstream conveyor lanes definedby the pair of guide rails would include sideby-side belts driven by thesame motive source at the same speed, or would include a single widebelt that would have the two pairs of guide rails defining the twodownstream conveyor lanes positioned above the single wider belt. Thissame wider belt would convey the objects delivered from the diverterdown the lengths of both of the first and second downstream conveyorlanes depending upon which of the two pairs of guide rails the diverterdirected the procession of objects to from the upstream conveyor.

In split path conveying systems comprising an upstream conveyorsupplying a procession of objects to at least two downstream conveyorlanes through a diverter, each of the downstream conveyor lanes wouldtypically employ some type of sensor along its length that wouldcommunicate with the diverter and control the operation of the diverterto direct the procession of objects conveyed by the upstream conveyor toone of the downstream conveyor lanes. For example, in a split pathconveyor having first and second downstream conveyor lanes, a lowsensor, either a mechanical sensor or an electric sensor, would bepositioned toward the outlet end of each of the first and seconddownstream conveyor lanes of the pair to sense the presence or absenceof objects on each of the first and second downstream conveyor lanestoward their outlet ends. In addition, each downstream conveyor lanewould have a full sensor adjacent its inlet end and a midway sensorpositioned along the length of the conveyor between its low sensor andfull sensor. These three sensors positioned along each of the downstreamconveyor lanes would give some indication as to the number of objectsaccumulated on each of the conveyor lanes that were available to beconveyed further down the conveyor system. The sensors would alsoprovide signals to a central processing unit CPU of the conveyor systemthat would control the operation of the diverter to replenish oraccumulate additional objects on each of the downstream conveyor lanesin response to signals of the sensors. When the low sensor of the firstdownstream conveyor lane would sense the absence of conveyed objects onthe first downstream conveyor lane indicating a low number of conveyedobjects accumulated in the first downstream conveyor lane, it would senda signal to the CPU that in turn would control the diverter causing thediverter to switch to direct objects conveyed by the upstream conveyorto the first downstream conveyor lane and then causing the gates of thediverter holding back objects on the upstream conveyor to open. Thediverter would include a sensor that would count objects conveyedthrough the diverter and the gate of the diverter would remain openuntil a number of objects was counted that would fill the space betweenthe low sensor and the diverter. In a like manner, when the midwaysensor or the full sensor of the first downstream conveyor lane wouldsense the absence of conveyed objects in the first downstream conveyorlane adjacent the sensor, it would send a signal to the CPU that wouldagain control the diverter to direct a number of bottles to the firstconveyor lane to fill the space between the midway sensor or the fullsensor and the diverter, depending on which sensor signals were receivedby the CPU. After each cycle of the upstream conveyor supplying a numberof bottles to either the first or second downstream conveyor lanes, thesensors and the CPU would then control the diverter to direct bottles tothe downstream conveyor lane having the fewest accumulated bottles.

In conveyor systems of the type describe above, the efficiency of theconveyor system is dependent on the speed in which it conveys objectsthrough the conveyor system. In a split path conveyor system of the typedescribed above, the switching of the diverter between the first andsecond downstream conveyor lanes would detract from the efficiency ofthe conveyor system. In the switching of the diverter the gate of thediverter is first closed holding back objects on the upstream conveyoras the diverter switches from the first to the second downstreamconveyor lane or from the second to the first downstream conveyor lane.When the switching operation is near completion the gates of thediverter are opened allowing objects on the upstream conveyor to bedirected to either one of the first and second downstream conveyorlanes. Each time the diverter switches between the first and secondconveyor lanes, the procession of objects being conveyed by theconveying system is stopped. Although the conveyance of objects isstopped for only a short period of time, multiplied by the number oftimes the diverter would switch between the first and second downstreamconveyor lanes the time period that the procession of objects conveyedby the conveyor system is stopped due to the switching of the diverterbecomes significant.

To make up for the lost time due to the switching operation of thediverter, increasing the speeds of the upstream conveyor and the firstand second downstream conveyor lanes was considered for split pathconveyor systems. However, in conveyor systems conveying lightweightobjects, for example belt conveyor systems conveying empty blow-moldedplastic bottles, the efficiency of the system could not be increased bysimply increasing the speed of the conveyor belts. As bottles conveyedon one of the conveyor belts would come into contact with bottlesaccumulated at the outlet end of the same belt, the increased speed ofthe conveyor would cause the conveyed bottles to impact with theaccumulated bottles with such a force that one or more of the conveyedbottles would be knocked backward from their upright orientations as aresult of the impact. Therefore, to prevent the lightweight objects, forexample blow-molded bottles, from falling over on impact along theconveyor system, the overall speed of the conveyor belts is limited andcannot be increased above the acceptable impact speed.

Controlling the speeds of the upstream conveyor and the conveyor of thefirst and second downstream conveyor lanes in split path conveyorsystems was also considered to increase their efficiency. It was thoughtthat the speed of the upstream conveyor and the speed of one of thefirst and second downstream conveyor lanes to which the diverter wasdirecting bottles could be increased after the gate of the diverter wasopened and then gradually decreased before the bottles provided by theupstream conveyor to the downstream conveyor would impact with bottlesalready accumulated on the particular downstream conveyor lane. The gateof the diverter would then be closed and the diverter would be switchedto the other downstream conveyor lane, the gates opened and the speedsincreased to quickly supply bottles from the upstream conveyor to theother downstream conveyor lane. However, because both the first andsecond downstream conveyor lanes extended over one wide conveyor belt ortwo side-by-side belts driven by the same motive source, increasing thespeed of one lane of the downstream conveyor to quickly supply it with anumber of bottles from the upstream conveyor would also result inincreasing the speed of the other lane of the downstream conveyor. Thiswould result in uncontrollable bottle impact situations. For example,increasing the speed of the upstream conveyor and the first downstreamconveyor lane to provide the first downstream conveyor lane with asufficient number of bottles to fill the space between its low sensorand the diverter would also result in increasing the speed of the secondconveyor lane. If a supply of bottles had been previously directed tothe second conveyor lane by the diverter to fill the space between themidway sensor of the second conveyor and the diverter, the increasedspeed of the first downstream conveyor lane would also increase thespeed of the second downstream conveyor lane causing the supply ofbottles provided to the second downstream conveyor lane to impact withthe bottles already accumulated on the second downstream conveyor laneat the increased speed. As a result, controlling the speeds of thedownstream conveyor increasing its speed to quickly supply bottles to aconveyor lane and then decreasing the speed before the bottles suppliedto the one particular conveyor lane impacted with bottles accumulated onthe one particular conveyor lane was not seen as a solution toincreasing the time efficiency of split path conveyor systems.

In increasing the speed at which processions of bottles were conveyedfrom the upstream conveyor through the diverter to one of the downstreamconveyors, it was observed that when the gates of the diverter wereclosed to switch the diverter between the downstream conveyors, if onlyone or a small number of bottles conveyed by the upstream conveyor wouldimpact with the closed gates some of the bottles would likely fall over.However, if the diverter gates were closed when a number of bottles wereaccumulated on the conveyor behind the diverter gates, the impact ofadditional bottles conveyed by the upstream conveyor with theaccumulated number of bottles would cushion the impact and reduce thelikelihood of bottles falling over. However, when the conveyor system isoperated at increased speeds it is not always possible to maintain anaccumulation of bottles on the upstream or infeed conveyor behind thediverter gates when the gates are closed to insure that individualbottles or small groups of bottles would not impact with the closedgates and possibly fall over.

In addition, as speeds are increased the force exerted by anaccumulation of objects on a diverter gate holding back the objects onthe surface of the moving conveyor would increase. This force couldincrease to the point where when the gate of the diverter is opened todirect the accumulated procession of objects down one of the downstreamconveyors the opening of the gate could cause the lead object or objectsto spring out of the gate and fall over in the conveyor path before theprocession of objects. This potential for objects falling over isfurther increased where the conveyor section includes a vacuum forholding objects down on the conveyor surface. The addition of vacuumfurther increases the pressure created in the held back procession ofobjects behind the diverter gate.

What is needed to overcome the deficiencies in split path conveyorsystems is an arrangement of sensors on the systems that provide a moreaccurate indication of the extent of accumulated conveyed objects oneach of the downstream conveyors supplied by the upstream conveyor, andseparate downstream conveyors with adjustable speed drive systems thatare controlled by the CPU of the downstream conveyors to increase thespeeds of the downstream conveyors in certain sensed conditions toquickly accumulate conveyed objects on the downstream conveyors and thendecrease the speeds of the downstream conveyors to avoid a level ofimpact of conveyed objects with accumulated objects on the downstreamconveyors that would cause some of the conveyed objects to be knockedover from their upright positions due to the impact.

Also what is needed to overcome the deficiencies in split path conveyorsystems is a mechanism by which the gaps that appear between objectsconveyed in a procession by the upstream conveyor to one of the twodownstream conveyors can be monitored to insure that the occurrence ofgaps between conveyed objects does not amount to a level where there isan insufficient number of objects or bottles conveyed by the upstreamconveyor to act as a cushion when the gates of the diverter are closedto cushion the impact of gapped accumulated bottles traveling toward thegate and later arriving objects or bottles with the objects accumulatedon the upstream conveyor behind the closed diverter gates. In addition,relieving the pressure of accumulated objects held behind the closedgates of the diverter just prior to the gates being opened would avoidthe problem of one or more objects being propelled through the gates andpotentially falling over in the conveyor path as the gates are opened.

SUMMARY OF THE INVENTION

The conveyor system of the invention in the illustrative embodiment tobe described supplies four lanes of conveyed objects to a palletizer.However, the features of the conveyor system of the invention could beemployed in supplying more than four lanes or fewer than four lanes ofconveyed objects, and the conveyor system has applications other thansupplying rows or lanes of objects to a palletizer. It should beunderstood that the description of the conveyor system of the inventionas ultimately including four lanes of conveyed objects that are suppliedto a palletizer is illustrative only and is not intended to limit theclaimed features of the invention. Also, in the illustrative embodimentof the conveyor system, the conveyors are belt-type conveyors thatconvey empty plastic blow-molded bottles. However, the inventivefeatures of the conveyor system could be employed in other types ofconveyor systems, for example air conveyor systems, and may also beemployed on conveyor systems in conveying other types of objects.

The illustrative embodiment of the conveyor system of the inventionemploys a single upstream or infeed conveyor, a pair of intermediateconveyors, and two pairs of downstream conveyors. Each of the conveyorsis a belt type conveyor, for example a belt conveyor manufactured byOuellette Machinery Systems, Inc. of Fenton, Mo. that employs a Rexnord®table top chain conveyor belt. Each of these conveyors have continuouslyrunning belts as the conveyor system is operated and have guide rails onopposite sides of the belts that direct the procession of bottles insingle file along each of the conveyors. The bottles are conveyed inupright orientations of the bottles on the belts and the belt topsurfaces are sufficiently smooth to enable the top surfaces to slidebeneath the conveyed bottles when the procession of conveyed bottles isheld back by a gate of the conveyor system allowing bottles toaccumulate on the conveyor.

Each of the conveyors of the conveyor system is driven by a motivesystem, for example an electric motor and a speed shiftable powertransmission system or an electric motor that can be controlled to varyits speeds, that is operable to run the conveyor at a plurality ofdifferent speeds and preferably at least a fast and a slow speed. Themotive system of each conveyor can adjust the speed of the conveyor beltindependently of the other conveyors.

The illustrative embodiment of the conveyor system employs threediverter assemblies with a first diverter assembly positioned betweenthe upstream or infeed conveyor and the pair of intermediate conveyorsand a pair of downstream diverter assemblies, second and third diverterassemblies, positioned between the pair of intermediate conveyors andthe two pairs of downstream conveyors. In the preferred embodiment thediverter assemblies are diverter models BD250-2 or BD350-2 manufacturedby Ouellette Machinery Systems, Inc. of Fenton, Mo. The divertersfunction like railroad track switches directing a procession of bottlessupplied by one conveyor to the diverter to one of the two conveyors atthe opposite side of the diverter. For example, the diverter between theupstream conveyor and the pair of downstream conveyors will selectivelydirect a procession of bottles conveyed by the upstream conveyor to oneof the pair of downstream conveyors. The diverter has a pair of spaced,vertical panels that are switchable between the pair of intermediateconveyors so that the diverter may direct the procession of bottlesconveyed by the upstream conveyor to either one of the pair ofintermediate conveyors depending on sensed conditions of bottlesaccumulated on the pair of intermediate conveyors. The diverter also hasa pair of gates, one mounted on each panel. The gates are operablebetween closed and open positions. In the closed positions they extendacross the conveyor path and hold back bottles conveyed by theparticular conveyor, allowing a number of bottles to accumulate on theconveyor behind the gate. In the opened positions they allow bottles tobe conveyed past the gates. Each of the diverters is also provided witha sensor, either mechanical or electrical and preferably a photo sensor,that is mounted on the panels and communicates with a central processingunit (CPU) of the system to count the number of bottles conveyed throughthe diverter. The CPU uses this information in controlling the openingand closing of the gates of the diverter assembly.

In the preferred embodiment of the conveyor system each of the pair ofintermediate conveyors and each of the two pairs of downstream conveyorshave a plurality of sensors positioned along the lengths of theconveyors between their inlet and outlet ends. Preferably, at least twosensors are positioned along the lengths of each of the conveyors. Inthe illustrative example three sensors are used with a low sensorpositioned adjacent the outlet end of the conveyor, a full sensorpositioned adjacent the inlet end of the conveyor and a midway sensorpositioned along the conveyor between the low sensor and full sensor.Preferably, the sensors employed are photo sensors that are capable ofdetecting the presence or absence of a bottle on the conveyor at thelocation of the sensor. In addition, the midway sensor of each conveyoris preferably positioned slightly toward the low sensor of each conveyorso that there is a greater distance between the midway sensor and thefull sensor than between the midway sensor and the low sensor. Thesensors of the conveyors communicate through a central processing unit(CPU) with the motive sources of the conveyors to control the changingof speeds of the individual conveyors depending on conditions sensed bythe sensors along the lengths of the conveyors. In addition, the sensorsof each conveyor communicate through the CPU with the diverterassemblies causing the gates of the diverter assemblies to open andclose and causing the diverter panels of the diverter assemblies toswitch between the conveyors supplied with bottles from the diverterassemblies depending on sensed conditions of the sensors. For example,if the sensors of a first conveyor of the pair of intermediate conveyorsare all opened indicating the absence of bottles at the low sensor, themidway sensor and the full sensor, these sensors send a signal to thefirst diverter assembly causing the diverter panels of the diverterassembly to be switched to the first intermediate conveyor and causingthe gate of the first diverter assembly to open so that a procession ofbottles is directed from the upstream conveyor through the diverterassembly to the first conveyor of the pair of intermediate conveyors.The signal sent by all three of the sensors along the first intermediateconveyor indicates to the diverter assembly that the first intermediateconveyor can be supplied with a number of bottles that would fill thelength of the first intermediate conveyor between the low sensor and thefirst diverter assembly. The counter photo sensor of the diverterassembly senses the bottles that pass by the gate and the CPU counts thebottles until a number of bottles that would fill the length of thefirst intermediate conveyor between the low sensor and the diverterassembly passes the gate, whereupon the diverter assembly will close thegate and switch the diverter panels to the second intermediate conveyorto supply bottles to the second intermediate conveyor as needed. Aftereach cycle of the upstream conveyor supplying a number of bottles toeither the first or second downstream conveyors, the sensors and the CPUwould then control the diverter to direct bottles to the downstreamconveyor having the fewest accumulated bottles. If the low sensor of thefirst intermediate conveyor senses the presence of bottles on theconveyor and the midway sensor and full sensor do not sense the presenceof bottles, the sensors cause signals to be sent to the diverterassembly causing it to switch the diverter panels to direct bottles fromthe upstream conveyor to the first intermediate conveyor. The sensorsalso send signals to the diverter assembly causing the diverter assemblyto open its gate and allow a number of bottles to pass through the gatethat is sufficient to fill the space between the midway sensor and thefirst diverter assembly. With this number of bottles counted by thesensor of the diverter assembly, the gate is controlled to close and thediverter panels are switched to the second intermediate conveyor tosupply bottles to that conveyor as needed. In addition, if while thegate is opened and the upstream conveyor is supplying a number ofbottles to the first intermediate conveyor that will fill the spacebetween the midway sensor and the full sensor and the low sensor opensindicating that the last of the bottles accumulated on the intermediateconveyor has passed the low sensor, the low sensor sends a signal to theCPU and the CPU counter counting bottles that pass the counter photosensor will change from counting a number of bottles that will fill thespace between the midway sensor and the diverter assembly to counting anumber of bottles that will fill the space between the low sensor andthe diverter assembly and then close the gate when this number ofbottles has passed by the diverter sensor. By converting the number ofbottles being counted by the CPU as the bottles are being counted theconveyor system saves time.

In addition, the conditions sensed by the low sensor, the midway sensorand the full sensor also control the speeds of each of the conveyors.For example, if each of the three sensors along the first intermediateconveyor sensed an open condition or the absence of bottles along thethree sensor positions of the conveyor, the sensors would send a signalto the CPU that would then control the motive sources of the upstreamconveyor and the first intermediate conveyor causing them to operate atslow speeds as the gate of the first diverter directing bottles to thefirst intermediate conveyor is opened and then to ramp up to high speedsto quickly supply the bottles from the upstream conveyor through thediverter to the first intermediate conveyor. When the counter sensor ofthe diverter determines that there are only a few bottles left to fillthe space between the low sensor and the diverter, then the CPU controlsthe motive sources of the upstream conveyor and the motive source of thefirst intermediate conveyor to ramp down to slow speeds at which thegate was opened. This reduces the impact force of the conveyed bottleson the first intermediate conveyor with any accumulated bottles on thefirst intermediate conveyor that are downstream of the low sensor andthus avoids a level of impact of the bottles that would cause bottles atthe end of the stream of conveyed bottles on the first intermediateconveyor from falling over. In a like manner, if the low sensor of thefirst intermediate conveyor senses the presence of bottles but themidway sensor and full sensor do not sense the presence of bottles, thenthe gate is opened to supply a number of bottles to the firstintermediate conveyor that will fill the space between the midway sensorand diverter and the speed of the upstream conveyor and the speed of thefirst intermediate conveyor are controlled to increase from the lowspeed at the time the gate is opened to the high speed. The upstreamconveyor and first intermediate conveyor are maintained at high speedsuntil the counter photo sensor at the diverter and the CPU detect thatonly a few bottles are left in the number of bottles supplied to thefirst intermediate conveyor at which point the speeds of the upstreamconveyor and first intermediate conveyor are reduced to slow speeds tominimize the impact of the bottles conveyed to the first intermediateconveyor with the bottles already accumulated on the first intermediateconveyor and the slower moving bottles also enable the gates to closebetween the last bottle counted and the first bottle to be held. In thismanner, bottles are quickly conveyed along each of the conveyors at highspeed, but then the speed of conveyance is reduced to avoid the problemof impacting of bottles at high speeds causing the bottles at the end ofa conveyed number of bottles from falling over.

Each of the pair of intermediate conveyors of the conveying system andthe two pairs of downstream conveyors of the conveying system have atleast two but preferably three photo sensors positioned along theirlengths that emit signals that communicate with the CPU which controlsthe gates and the panels of the diverters that direct bottles to theconveyors and also controls the motive sources of each of the conveyorsand the photo counters of each of the diverter assemblies as describedabove.

The upstream or infeed conveyor is also provided with sensors that sensegaps between adjacent bottles being conveyed by the infeed conveyor tothe intermediate or downstream conveyors. This information iscommunicated to the CPU and the gaps for a number of bottles beingconveyed by the upstream conveyor to the downstream conveyors is summed.The sum of the gaps is compared to an acceptable predetermined gap sizefor the number of bottles being conveyed to the downstream conveyors toinsure that the summed gap does not become too large as to present thepotential problem of too few bottles being accumulated before the firstdiverter gates to act as a cushion when the gates are closed. If thepredetermined total gap is reached by the gaps sensed by the sensor andsummed by the CPU the upstream conveyor will continue to operate at areduced speed while an additional set number of bottles is conveyed pastthe sensor. If the gap count does not correct itself as the set numberof bottles is conveyed past the sensor the CPU will control the upstreamconveyor to close the gates of the first diverter to avoid the potentialproblem of too few bottles accumulated behind the gates to cushion thebottles traveling toward the gate and later arriving bottles impactingwith each other on the conveyor and potentially falling over. With thegates closed the procession of bottles are again allowed to accumulateon the upstream conveyor for a predetermined time period, followingwhich the gates are opened.

In order to insure that an accurate measurement is made of the gapsbetween bottles and the total summed gaps that pass by the sensor, theupstream conveyor employs a unique sensor arrangement of a first senderand receptor pair and a second sender and receptor pair that arepositioned side by side on opposite sides of the conveyor to obtain anaccurate gap count.

In addition, to avoid the problem of the pressure build up in aprocession of bottles accumulated on the upstream conveyor and held backby the first diverter gate potentially projecting one or more bottlesoutwardly from the diverter gate as the gate is opened, the opening ofthe diverter gate is timed so that the upstream conveyor is allowed todecrease in speed just prior to the opening of the first diverter gate,thereby reducing the pressure among the bottles accumulated behind thefirst diverter gate on the upstream conveyor. Furthermore, when a vacuumsystem is employed with the upstream conveyor to assist in holding downconveyed bottles on the top surface of the conveyor, the vacuum createdby the vacuum system drawing bottles down onto the upstream conveyorwill decrease a short time before the opening of the first diverter gateto further reduce the pressure built up among bottles accumulated behindthe first diverter gate and thereby avoid the problem of one or twobottles projecting forwardly through the gate as the gate is opened andpotentially falling over.

The split path conveying system of the invention constructed in themanner described above significantly increases the time efficiency ofthe split path conveyor system over those of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention are set forth in the followingdetailed description of the preferred embodiment of the invention and inthe drawing figures wherein:

FIG. 1 is a schematic block representation of how FIGS. 2 through 6 ofthe drawings are arranged together to show a plan view of an entireconveyor systems of the preferred embodiment of the invention;

FIG. 2 is a plan view of the upstream conveyor of the conveyor systemand the first diverter assembly as well as the inlet ends of the firstand second intermediate conveyors;

FIG. 3 is a plan view of a portion of the first and second intermediateconveyors;

FIG. 4 is a plan view of the outlet ends of the first and secondintermediate conveyors as well as the second and third diverterassemblies of the conveyor system and the inlet ends of the first andsecond pairs of downstream conveyors;

FIG. 5 is a plan view of portions of the first and second pairs of thedownstream conveyors;

FIG. 6 is a plan view of the downstream conveyors merging into a stopgate and a row former that prepares rows of bottles conveyed by theconveyor system for arrangement on pallets;

FIG. 7 is a top plan view of one of the diverter assemblies;

FIG. 8 is a partial plan view of the diverter assembly panels and gates;

FIG. 9 is a partial end elevation view of the diverter assembly panelsand the gates and counter sensor;

FIG. 10 is an enlarged view of a transfer assembly of the conveyorsystem;

FIG. 11 is a plan view of the upstream conveyor similar to FIG. 2 butshowing additional modifications to the upstream conveyor;

FIG. 12 is a schematic block representation similar to that of FIG. 1but showing how FIG. 11 of the drawings is arranged relative to FIGS. 3through 6;

FIG. 13 is a schematic representation of how prior art photosensorsfunction and their disadvantages;

FIG. 14 is a transverse section view through the upstream conveyor ofFIG. 11;

FIG. 15 is a plan view taken along the line 15—15 of FIG. 14; and

FIG. 16 is a plan view similar to those of FIGS. 4, 5 and 6 but showingimprovements made by the positioning of additional photo sensors.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawing figures, FIG. 1 shows a block diagram arrangement of howFIGS. 2 through 6 are arranged to show an embodiment of the conveyorsystem of the present invention. The illustrative embodiment of theconveyor system shown in FIGS. 2 through 6 conveys a procession ofobjects, in the illustrative embodiment empty blow-molded plasticbottles, from left to right in each of the figures to a bottle stop gate10 shown in FIG. 6 that accumulates four rows of bottles behind the stopgate and that selectively opens and closes to supply the accumulatedrows of bottles to a row former 12 that ultimately arranges the rows ofbottles in layers on a pallet (not shown). The use of the conveyorsystem of the invention to provide four rows of bottles that areaccumulated by the stop gate 10 for the row former 12 is only oneillustrative embodiment of the conveyor system of the invention. Thefeatures of the conveyor system of the invention could be employed insupplying more than four rows of bottles, or could be used to supplyfewer than four rows of bottles. The features of the conveyor systemcould also be used to split one infeed conveyor into three downstreamconveyors and then further split the conveyors to supply any even or oddnumbers of rows of bottles. In addition, the conveyor system hasapplications other than supplying rows of bottles to a palletizer. Itshould be understood that the description of the conveyor system of theinvention as ultimately providing four rows of bottles to a machinewhere the bottles are accumulated in the four rows is illustrative onlyand is not intended to limit the claimed features of the invention.Also, in the illustrative embodiment of the conveyor system, theconveyors are belt type conveyors that convey empty plastic blow-moldedbottles. However, the inventive features of the conveyor system could beemployed in other types of conveyor systems, for example air conveyorsystems, and may also be employed on conveyor systems that convey othertypes of objects.

The conveyor system of the invention is comprised of known types ofconveyors, diverter assemblies, motive systems and photo sensors thatare schematically represented in the drawing figures to simplify thedescription of the conveyor system. The novel arrangement of these knowncomponent parts of the conveyor system and the manner in which theyinteract with each other enables the conveyor system to split a singlepath of conveyed plastic bottles at the input of the conveyor systeminto four lanes of accumulated plastic bottles at the output of theconveyor system in a more time efficient manner than that of prior artsplit path conveyor systems.

The illustrative embodiment of the conveyor system of the inventionshown in FIGS. 2 through 6 employs a single upstream or infeed conveyor16, a pair of intermediate conveyors 18, and two pairs of downstreamconveyors 22 for a total of four downstream conveyors. Each of theconveyors is a belt type conveyor, for example a belt conveyormanufactured by Ouellette Machinery Systems, Inc. of Fenton, Mo. thatemploys a Rexnord® table top chain conveyor belt. Referring to FIG. 2,the upstream conveyor 16 has a length between its inlet end 24 and itsopposite outlet end 26. A moving table top surface or belt surface 28extends the entire length of the conveyor. The belt surface 28 runscontinuously during the operation of the conveyor, but its speed changesas will be explained. Guide rails 32 are positioned along the oppositesides of the belt surface 28 and are spaced apart from each other adistance that is slightly larger than the width of the objects conveyedby the conveyor, in this case empty plastic blow-molded bottles. Thisspacing of the guide rails 32 directs a procession of bottles conveyedby the upstream conveyor 16 in single file along the length of theconveyor. The bottles are conveyed in upright orientations of thebottles on the belt surface 28 and the belt surface is sufficientlysmooth to enable the surface to slide beneath the conveyed bottles whenthe procession of conveyed bottles is held back on the upstream conveyor16 when accumulating bottles on the conveyor. An infeed sensor 34, amechanical or electrical sensor but preferably a photo sensor, ispositioned at a predetermined location along the upstream conveyor 16.The infeed sensor 34 senses the presence or absence of bottlesaccumulated on the conveyor back to the location of the sensor. Theposition of the sensor ensures there are enough bottles accumulated onthe upstream conveyor 16 to act as a cushion that absorbs the force ofimpact of other bottles conveyed on the upstream conveyor that impactwith the bottles held back on the conveyor to the infeed sensor 34 orbeyond.

The upstream conveyor 16 is driven by a motive source 36. The motivesource is comprised of an electric motor and a speed shiftable powertransmission system, for example a belt and pulley system withelectrically activated clutches, or an electric motor that can becontrolled to operate at various speeds. This enables the motive system36 to drive the upstream conveyor 16 at a plurality of different speeds,and preferably at least three speeds.

Positioned at the outlet end 26 of the upstream conveyor 16 is adiverter assembly 42. In the preferred embodiment of the conveyorsystem, the diverter assembly 42 is a diverter model BD250-2 or modelBD350-2 manufactured by Ouellette Machinery Systems, Inc. of Fenton, Mo.Diverter assemblies of this type are known in the art and its generalconstruction is shown in FIGS. 7, 8 and 9. The diverter assembly 42 isbasically comprised of gates 44 mounted on a pair of switchable diverterpanels 46. The gates 44 are pneumatically operated and pivot on outletends of the panels between closed and opened positions shown in FIGS. 8and 9, respectively. In the closed position of the gates they extendinto the conveyor path of bottles being conveyed by the upstreamconveyor 16 and hold back bottles conveyed by the conveyor, allowing anumber of bottles to accumulate on the conveyor behind the gates 44 orto the left of the gates as viewed in FIG. 2. In the opened position thegates 44 allow bottles to be conveyed by the upstream conveyor 16 pastthe gates and through the diverter panels 46. The diverter panels 46function like railroad track switches directing a procession of bottlesconveyed by the upstream conveyor 16 through the diverter assembly 42 toone of the two intermediate conveyors 18. The two switched positions ofthe diverter panels 46 are represented by the parallel pairs of dashedlines shown in the diverter assembly 42 in FIG. 2. The diverter panels46 are pneumatically operated and are switchable between the twopositions of the panels represented by the dashed lines in FIG. 2communicating the upstream conveyor 16 with either one of the pair ofintermediate conveyors 18. The diverter assembly 42 is also providedwith a counter photo sensor 48 mounted on the outlet ends of thediverter panels 46. The sensor 48 could be either mechanical orelectrical but preferably is a photo sensor that senses bottles conveyedpast the counter sensor 48 as they are directed through the diverterassembly panels 46. The counter sensor 48 emits signals for the numberof bottles conveyed through the diverter assembly 42 and thisinformation is used in controlling the opening and closing of thediverter gates 44 as well as the speeds of the conveyors as will beexplained.

The pair of intermediate conveyors 18 each have an inlet section 18 aand an outlet section 18 b. Each inlet section 18 a functions to quicklysupply bottles to its outlet section 18 b to keep bottles accumulated onits outlet section 18 b while minimizing the impact of bottles suppliedby the inlet section 18 a with bottles that may be accumulated on theoutlet section 18 b as well as on the inlet section 18 a. Theintermediate conveyor sections 18 a and 18 b are each constructed insubstantially the same manner as the upstream conveyor and componentparts of the intermediate conveyor sections are identified by the samereference numbers as the component parts of the upstream conveyorfollowed by a prime (′) and a double prime (″). Like the upstreamconveyor, each of the intermediate conveyor sections 18 a, 18 b has aninlet end 24′, 24″ and an opposite outlet end 26′, 26″, a belt surface28′, 28″, guide rails 32′, 32″ and a motive source 36′, 36″. However,each of the first 52 and second 54 intermediate conveyors differs fromthe upstream conveyor 16 in that they include a plurality of sensorspositioned along their inlet section 18 a lengths between their inlet24′ and outlet 26′ ends. Preferably, the three sensors are positionedalong the inlet section lengths of the intermediate conveyors 52, 54with each conveyor having a low sensor 56 positioned toward the outletend 26′ of the conveyor inlet section 18 a where it will sense as lowsupply of bottles accumulated on the conveyor section, a full sensor 58positioned toward the inlet end 24′ of the conveyor section where itwill sense a full supply of bottles accumulated on the conveyor sectionand a midway sensor 62 positioned along the length of each conveyorinlet section between the low sensor and the full sensor. The sensors56, 58, 62 can be mechanical or electrical sensors but are preferablyphoto sensors that are capable of detecting the presence or absence of abottle on the inlet sections of each of the intermediate conveyors 52,54 at the location of the sensor. In addition, the midway sensors 62 ofthe intermediate conveyors 52, 54 are positioned slightly toward the lowsensors 56 of the conveyors so that there is a greater distance betweenthe midway sensor 62 and the full sensors 58 of the conveyors thanbetween the midway sensors 62 and the low sensors 56.

The sensors 56, 58, 62 of each of the intermediate conveyors 52, 54communicate through a central processing unit 64 with the motive source36 of the upstream conveyor as well as with the infeed sensor 34, thediverter assembly gates 44, the diverter panels 46 and the countersensor 48 of the diverter assembly 42. The CPU 64 is programmed tocontrol the operation of the motive source 36 of the upstream conveyor16 adjusting the speed of the motive source and thereby the speed of theconveyor as well as the opening and closing of the first diverterassembly gates 44, the switching of the diverter panels 46 between theirtwo positions and the resetting of the CPU counter which communicateswith the counting photo sensor 48 to count a particular number ofbottles that pass through the diverter assembly 42.

At the outlet ends 26″ of the outlet sections of the intermediateconveyors 18 are second 66 and third 68 diverter assemblies that aresubstantially identical to the first diverter assembly 42 describedearlier. Because the second 66 and third 68 diverter assemblies includethe same component parts as the first diverter assembly 42, thosecomponent parts are identified by the same reference numbers followed bya prime (′). Like the first diverter assembly 42, each of the second 66and third 68 diverter assemblies include a gate 44′, diverter panels 46′and a counter photo sensor 48′. Each of these component parts of thesecond 66 and third 68 diverter assemblies operates in the same manneras those of the first diverter assembly 42.

The second diverter assembly 66 operates to direct a procession ofbottles conveyed by the first intermediate conveyor 52 to one of thepairs of downstream conveyors 22 or to a first 82 or second 84 of thedownstream conveyors. The third diverter assembly 68 operates to directa procession of bottles conveyed by the second intermediate conveyor 54to the second pair of downstream conveyors 22 or to the third 86 orfourth 88 downstream conveyor. Each of the four downstream conveyors 82,84, 86, 88 are duplications of the inlet sections of the intermediateconveyors 52, 54 and like the intermediate conveyors, each includes alow photo sensor 92, a full photo sensor 94 and a midway photo sensor96. Like the inlet sections of the intermediate conveyors, the low photosensor 92 of the downstream conveyors are positioned toward the outletends 98 of the conveyors, the full photo sensors 94 of the downstreamconveyors are positioned toward the inlet ends 102 of the conveyors, andthe midway sensors 96 are positioned along the lengths of the conveyorsbetween the low sensors and full sensors. Like the inlet sections of theintermediate conveyors, the midway sensors 96 are positioned slightlytoward the low sensors 92 so that there is a greater distance betweenthe midway sensors 96 and the full sensors 94 than between the midwaysensors 96 and the low sensors 92. The sensors of each of the downstreamconveyors communicate through the central processing unit 64 with themotive sources 104 of the conveyors to control their speeds. Inaddition, the sensors of the downstream conveyors also communicate withthe second 66 and third 68 diverter assemblies, and more specificallythe gates 44′, diverter panels 46′ and the counter sensors 48′ of thetwo diverter assemblies through the central processing unit 64 of theconveyor system. The outlet ends 98 of the downstream conveyors definethe end of the conveyor system of the invention and communicate withfour outlet lanes 106 that accumulate bottles received from thedownstream conveyors in four rows that are routed to the bottle stopgate 10 and the row former 12, described earlier.

The operation of the intermediate conveyors 18 is basically duplicatedby each of the downstream conveyors 82, 84, 86, 88 and therefore onlythe operation of the two intermediate conveyors 52, 54 and in particularthe inlet section of the first intermediate conveyor 52 will bedescribed in detail.

In operation of the conveyor system of the invention, the upstreamconveyor 16 receives a procession of objects, in this example empty,plastic blow-molded bottles, from a source of the bottles (not shown) atthe inlet end 24 of the conveyor. In operation of the conveyor systemthe upstream conveyor 16, as well as the intermediate conveyors 18 andthe downstream conveyors 24 are continuously running and only theirspeeds are changed as will be described. The procession of bottles areconveyed along the upstream conveyor 16 to the right as shown in FIG. 2to the first diverter assembly 42 and are held back by the gates 44 whenthe gates are in their closed positions. The bottles can accumulate onthe upstream conveyor 16 with the gates 44 closed and the conveyor willcontinue to run with the belt surface 28 of the conveyor sliding beneaththe bottom surfaces of the upright oriented bottles accumulated behindthe first diverter gates 44. The infeed sensor 34 positioned along theupstream conveyor 16 ensures that a certain number of bottles areaccumulated on the upstream conveyor between the diverter gates 44 andthe infeed sensor 34. The infeed sensor 34 sends a signal to the CPU 64that indicates the presence or absence of bottles accumulated on theinfeed conveyor behind the gates 44 at the position of the infeed sensor34. The CPU in turn controls the operation of the first diverter gates44 preventing the gates from opening at any time the infeed sensor 34senses the absence of bottles accumulated on the infeed conveyor. Thismaintains a certain number of bottles between the infeed sensor 34 andthe gates 44 that function as a cushion for subsequent bottles that aresupplied to the inlet end 24 of the upstream conveyor that impact withthe accumulated bottles on the upstream conveyor. The force of impact ofthe subsequent conveyed bottles is distributed through all of thebottles that are accumulated between the diverter gates 44 and theinfeed sensor 34 and in this manner the force of impact is lessened tothe extent that the impact will not cause the subsequent impactingbottle to fall over on the infeed conveyor. Thus, by the infeed sensor34 maintaining a certain number of bottles accumulated on the upstreamconveyor 16 between the diverter gates 44 and the infeed sensor 34, anysubsequent bottles that are conveyed by the upstream conveyor and impactwith the accumulated bottles on the upstream conveyor will remain intheir upright orientations. When the gates 44 of the first diverter areopened to supply a procession of bottles to either of the intermediateconveyors 18, should the infeed sensor 34 detect the absence of a bottleat its position along the upstream conveyor, for example the absence issensed for a fraction of a second, the gates 44 of the first diverterwill immediately close once the photo sensor 48 of the first diverterhas sensed that a bottle has completely passed the gates to ensure thatthe gates 44 do not close and pinch a bottle between the gates as theyare closed. Because the gates 44 will allow one or two bottles to passby the gates before they are closed, the infeed sensor 34 is positionedalong the upstream conveyor a sufficient distance to ensure that thereare enough bottles accumulated between the diverter gates 44 and theinfeed sensor 34 to function as a cushion even when one or two of theaccumulated bottles are allowed to pass by the gates before the gatesare closed.

The photo sensors 56, 68, 62 along the first 52 and second 54intermediate conveyors sense the presence or absence of bottlesaccumulated on the inlet sections 18 a of the intermediate conveyors andprovide signals to the central processing unit 64 that are indicative ofthe sensed presence or absence of a bottle at the particular location ofthe photo sensors. The central processing unit 64 uses this informationprovided by the intermediate conveyor sensors 56, 58, 62 to control theoperation of the first diverter assembly 42 and in particular the gates44 and diverter panels 46 of the diverter assembly. In addition, thecentral processing unit 64 uses the information provided by the sensors56, 58, 62 to control the speed of the motive source 36 of the upstreamconveyor 16 as well as the speed of the motive source 36′ of either thefirst or second intermediate conveyor inlet section 18 a being suppliedwith bottles by the first diverter.

For example, if the photo sensors 56, 58, 62 of the first intermediateconveyor 52 are all open or do not detect the presence of a bottleadjacent the photo sensor locations, these photo sensors send signals tothe CPU 64 that indicate at least a portion of the first intermediateconveyor between the low sensor 56 and the first diverter assembly 42does not contain any accumulated bottles. The remainder of the firstintermediate conveyor 52 including the outlet section 18 b and theportion of the inlet section 18 a downstream of the low photo sensor 56,or between the low photo sensor 56 and the second diverter 66, couldcontain an accumulation of bottles or could also be absent ofaccumulated bottles. Regardless, the CPU 64 will send a signal to thefirst diverter assembly 42 causing it to switch the diverter panels 46to direct bottles received from the upstream conveyor 16 to the inletsection 18 a of the first intermediate conveyor 52 and then to open thegates 44 for a period of time that would allow a number of bottlessufficient to fill the space between the low sensor 56 and the firstdiverter assembly 42 to pass through the diverter assembly 42. Thebottles that pass through the diverter assembly 42 are counted by theCPU and the count photo sensor 48 until the pre-determined number passesthrough the diverter assembly at which point the conveyors slow down andthe gates 44 are closed. This allows the number of bottles that willfill the space between the low sensor 56 and the first diverter assembly42 to be accumulated on the first intermediate conveyor 52. If bottleswere previously accumulated on the outlet section 18 b of the firstintermediate conveyor between the low sensor 56 and the second diverterassembly 66, then this last supply of bottles sent to the firstintermediate conveyor would fill the conveyor. If the outlet section 18b of the first intermediate conveyor 52 had no bottles accumulatedbetween the low sensor 56 and the second diverter assembly 66, then thenumber of bottles supplied to the first intermediate conveyor 52 by thefirst diverter assembly 42 will be conveyed by the first intermediateconveyor completely past all three sensors 56, 58, 62 to the outletsection 18 b of the first intermediate conveyor 52 and the seconddiverter assembly 66. The three sensors would again sense the absence ofbottles between the low sensor 56 and the first diverter 42 and againsend signals to the CPU that would cause the CPU to control the firstdiverter assembly 42 to again open its gates 44 and channel a number ofbottles to the first intermediate conveyor 52 that would fill the spacebetween the low sensor 56 and the first diverter 42 provided that duringthe time the bottles are being supplied by the first diverter to thefirst intermediate conveyor the sensors of the second intermediateconveyor do not open indicating that it needs bottles.

If the low sensor 56 of the first intermediate conveyor 52 senses thepresence of bottles on the inlet section 18 a of the conveyor and themidway sensor 62 and full sensor 58 do not sense the presence ofbottles, the sensors send signals to the CPU 64 that indicate a numberof bottles have been accumulated on the first intermediate conveyor 52at least to the position of the low sensor 56 along the conveyor.However, the bottles could also be accumulated back behind the lowsensor 56 to a position just downstream of the midway sensor 62 of theconveyor where they would not be detected by the midway sensor.Therefore, the central processing unit 64 receiving these signals fromthe three sensors will control the first diverter assembly directing thediverter panels 46 of the diverter assembly to supply bottles conveyedby the upstream conveyor 16 to the first intermediate conveyor 52 andthen opening the gates 44 of the diverter 42. The central processingunit 64 will also receive signals from the counter photo sensor 48 ofthe first diverter assembly 42 as bottles pass the sensor and count anumber of bottles sufficient to fill the space between the midway sensor62 and the first diverter assembly 42. Once this number of bottles iscounted, the gates 44 are controlled to close and the diverter panels 46are controlled to switch over to the second intermediate conveyor 54 tosupply bottles to that conveyor if the sensors of the second conveyorare open, provided that during the time the bottles are being suppliedto the first intermediate conveyor the low sensor does not open and thecount of bottles being supplied is converted to a larger number ofbottles in the manner explained below. In a like manner, if only thefull sensor 58 is open indicating the absence of bottles on the firstintermediate conveyor at the full sensor, and if none of the sensors oronly the full sensor of the second intermediate conveyor 54 is opened,then the first diverter assembly will be controlled to direct a numberof bottles to the first intermediate conveyor to fill the space betweenthe full sensor 58 and the first diverter assembly 42.

In addition, if the midway and full sensors of the first intermediateconveyor 52 sense the absence of bottles and the CPU controls the gates44 of the first diverter assembly 42 to open and controls the upstreamconveyor 16 to supply a number of bottles to the first intermediateconveyor 52 to fill the space between the midway sensor 62 and the firstdiverter 42, and the low sensor 56 along the first intermediate conveyor52 then opens indicating that the last of the bottles previouslyaccumulated on the intermediate conveyor 52 has passed the low sensor56, the low sensor signal sent to the central processing unit 64 willcause it to reset the CPU counter to change between the number ofbottles that will fill the space between the midway sensor 62 and thefirst diverter assembly 42, to the number of bottles that will fill thespace between the low sensor 56 and the first diverter assembly and willthen close the gates 44 when this number of bottles has passed by thediverter counter sensor 48. By converting the number of bottles beingcounted by the CPU from a smaller number to a larger number as thebottles are being counted, a switch of the divert and its loss ofconveying time are eliminated and more uninterrupted conveying time isgained, thus improving time efficiency of the conveyor system.

In addition, the spacing between the full sensor 58 and the midwaysensor 62 is specifically determined to be slightly larger than thespacing between the midway sensor 62 and the low sensor 56 to avoidsending inaccurate signals to the central processing unit 64 that wouldrepresent that no bottles are accumulated on the intermediate conveyorbetween the midway sensor 62 and the low sensor 56. When the centralprocessing unit controls the first diverter assembly 42 to supply anumber of bottles to the first intermediate conveyor 52 to fill thespace between the midway sensor 62 and the first diverter assembly 42 asdescribed above, this number of bottles conveyed along the firstintermediate conveyor 52 cannot fit between the midway sensor 62 and thelow sensor 56 without being detected by one or both of the sensors dueto the smaller spacing between the midway sensor and low sensor thanthat between the full sensor and the midway sensor. Thus, the threesensors 56, 58, 62 of the intermediate conveyor 52 will not provide aninaccurate signal to the central processing unit 64 indicating that noneof the sensors detect the presence of bottles on the first intermediateconveyor 52 when a number of bottles supplied to the intermediateconveyor to fill the space between the midway sensor 62 and the firstdiverter assembly 42 has moved further down the intermediate conveyor toa position between the midway sensor 62 and the low sensor 56.

In addition, the conditions sensed by the low sensor 56, the midwaysensor 62 and the full sensor 58 also control the speed of the motivesources 36 of the upstream conveyor 16 and the speeds of the motivesources 36′ of the first 52 and second 54 intermediate conveyors. Forexample, if each of the three sensors 56, 58, 62 positioned along thefirst intermediate conveyor 52 sensed an open condition or the absenceof bottles along the three sensor positions of the conveyor, the sensorswould send these signals to the central processing unit 64 which wouldcontrol the motive source 36 of the upstream conveyor 16 and the motivesource 36′ of the inlet section 18 a of the first intermediate conveyorto both operate at first a low speed, for example 100 feet per minute asthe gates 44 of the diverter assembly 42 are opened. After opening ofthe gates 44, the speeds of the upstream conveyor 16 and the inletsection 18 a of the first intermediate conveyor 52 would be controlledto increase up to a high speed, for example 240 feet per minute. Thisincreased speed would quickly supply the bottles from the upstreamconveyor 16 to the inlet section 18 a of the first intermediate conveyor52 through the diverter 42. When the CPU, receiving counting signalsfrom the counter sensor 48 of the first diverter assembly 42, determinesthat there are only a few bottles left to be supplied to the bottlecount by the upstream conveyor 16 to fill the space between the lowsensor 56 and the first diverter assembly 42, then the CPU will controlthe motive sources of the upstream conveyor and the first intermediateconveyor to decrease the speeds of the conveyors, for example back to aslower speed of 90 feet per minute, and then close the gates after thepredetermined number of bottles had passed. After the gates 44 areclosed the speeds can then be increased to 100 feet per minute inpreparation of opening the gates again. This reduces the impact force ofthe bottles conveyed on the upstream conveyor 16 toward the inletsection 18 a of the first intermediate conveyor 52 with any accumulatedbottles that may be on the outlet section 18 b or the inlet section 18 aof the first intermediate conveyor that are downstream of the low sensor56 and/or downstream of the midway sensor 62, and thus avoids a level ofimpact of the bottles that would cause bottles at the end of the streamof bottles conveyed from the upstream conveyor 16 from falling over. Italso minimizes the impact of bottles conveyed on the upstream conveyor16 with the closed gates 44.

In a like manner, if the low sensor 56 of the first intermediateconveyor 52 senses the presence of bottles accumulated on the conveyorbut the midway sensor 62 and the full sensor 58 do not sense thepresence of bottles, then the central processing unit 64 will controlthe speeds of the upstream conveyor and the inlet section 18 a of thefirst intermediate conveyor 52 setting them at slow speeds as the gates44 of the first diverter assembly are opened. After the gates areopened, the central processing unit 64 increases the speeds of theupstream motive source 36 and the motive source 36′ of the inlet sectionof the first intermediate conveyor 52 from the slow speeds at the timethe gates are opened to the high speeds. The gates 44 remain opened asdescribed earlier to supply a number of bottles from the upstreamconveyor 16 to the first intermediate conveyor 52 that will fill thespace between the midway sensor 62 and the first diverter assembly 42.Both conveyors are maintained at the high speeds until the CPUdetermines from the signals supplied by the counter sensor 48 of thefirst diverter assembly 42 that only a few bottles are left in thenumber of bottles supplied to the first intermediate conveyor 52 atwhich point the central processing unit 64 decreases the speeds of theupstream conveyor 16 and the inlet section 18 a of the firstintermediate conveyor 52 back to the slow speeds before the gates 44 areclosed. This minimizes the impact of the bottles conveyed from theupstream conveyor 16 to the first intermediate conveyor 52 with bottlesthat may be already accumulated on the first intermediate conveyor. Italso minimizes the impact of bottles conveyed on the upstream conveyorwith the closed gates 44. In this manner, bottles are quickly conveyedfrom the upstream conveyor 16 on to the intermediate conveyor 52 at ahigh speed, but the speed of conveyance is then reduced to avoid theproblem of impacting of bottles at high speeds causing the bottles atthe end of a conveyed number of bottles from falling over.

The operation of the second intermediate conveyor 54 by the signals fromthe three sensors 56, 58, 62 along the conveyor sent to the centralprocessing unit 64 is the same as that described above with reference tothe first intermediate conveyor 52. In addition, the operation of eachof the downstream conveyors 82, 84, 86, 88 and their associated outletsections of the intermediate conveyors 52, 54 is controlled by thecentral processing unit 64 in response to signals received from thephoto sensors 92, 94, 96 of these conveyors in the same manner as thatdescribed above with reference to the upstream conveyor 16 and the firstintermediate conveyor 52. Thus, the central processing unit 64 controlsthe switching of the diverter panels 46′ of the second diverter assembly66 and third diverter assembly 68 and also controls the opening andclosing of the gates 44′ of the second and third diverter assemblies inthe same manner described above with reference to the first diverterassembly 42. The central processing unit 64 also controls the speeds ofthe motive sources 36″ of the outlet sections 18 b of the first 52 andsecond 54 intermediate conveyors and the motive sources 104 of thedownstream conveyors when supplying bottles to the four downstreamconveyors 82, 84, 86, 88 through the second and third diverterassemblies 66, 68 in the same manner described above with reference tothe upstream conveyor 16 and the first intermediate conveyor 52. In thismanner, the split path conveying system of the invention described abovesignificantly increases the time efficiency of the conveyor system overthose of the prior art in accumulating rows of bottles at the outlet end98 of the conveyor system.

FIG. 10 is an enlarged view of a transfer assembly positioned at thedownstream conveyor outlet ends 98. The transfer assembly functions toposition the accumulated bottles delivered at the downstream conveyoroutlet ends 98 into at least four side-by-side rows of bottles that areconveyed to the bottle stop gate 10 and the row former 12. The transferassembly includes a plurality of row conveyors, in the example shown inFIG. 10, seven row conveyors 112, 114, 116, 118, 122, 124, 126 that arearranged side-by-side at the downstream conveyor outlet ends 98.Although seven row conveyors are shown, the number could be increasedfor a larger number of downstream conveyors. The two outer most rowconveyors 112, 126 can be table top conveyors like those employed in theconveyor system described earlier. These two conveyors 112, 126 aredriven by their own motive source 130. The interior five row conveyors114, 116, 118, 122, 124 are flex chain belt conveyors that can conveyobjects around curves. Each of these interior conveyors can have theirspeed independently adjusted by its own motive source at the palletizerend. However, if the row conveyors leading to the palletizer did nothave to travel around a curve and could extend straight to thepalletizer, then it would be preferred that all of the row conveyors betable top chain conveyors. As shown in FIG. 10, four of the rowconveyors including the two outer most conveyors 112, 126 and a pair ofthe inner conveyors 116, 122 extend to the left in FIG. 10 to inlet ends128 of these four conveyors that are interleaved with the downstreamconveyer outlet ends 98. The outer most row conveyors 112, 126 extend instraight paths from their inlet ends 128 to opposite ends 132 of thesetwo conveyors that are positioned just before the curve in the flexchain conveyors. Three of the internal flex chain conveyors 114, 118,124 have inlet ends 134 that are aligned with the four downstreamconveyor outlet ends 98 but are spaced from the outlet ends.

To bridge the gap between the inlet ends 134 of several of the rowconveyors 114, 118, 124, pluralities of pairs of guides are employed.These include a first plurality of pairs of directional guides 136 and aplurality of pairs of combiner guides 138 that define the outlet lanes106 of the conveyor. Each of the pairs of guides are basically straightpairs of rails or panels that are spaced a distance apart that issufficiently wide to enable bottles conveyed by the conveyor to passbetween the guides and be directed by the guides as they are conveyed.As seen in FIG. 10, each of the pairs of directional guides 136 haveinlet ends 142 that are positioned over the downstream conveyor outletends 98. Each of the pairs of directional guides 136 is supported overthe conveyors in angled orientations of the guides so that the inletends 142 of the directional guides 136 are positioned over one of thefour downstream conveyors adjacent their outlet ends 98 and the outletends 144 of each pair of directional guides 136 is positioned over oneof the row conveyors 112, 116, 122, 132. Thus, as bottles are conveyedon the downstream conveyors toward the conveyor outlet ends 98 the pairsof directional guides 136 shift the bottles transversely across thedownstream conveyors onto the row conveyors 112, 116, 122, 126.

The outlet ends 144 of the directional guides 136 are positionedadjacent inlet ends 146 of the combiner guides 138. As the combinerguides 136 extend in the downstream direction they are angled across therow conveyors so that the outlet ends 148 of the combiner guides 138 areall positioned closely side-by-side. In addition, the combiner guideoutlet ends 148 are all positioned over three of the flex chain rowconveyors 118, 122, 124 that convey the four rows of bottles to thebottle stop gate 10 and the row former 12. The directional guides 136and the combiner guides 138 are shown with only a small spacing betweenthem for directing small diameter bottles. The directional guides andthe combiner guides can be adjusted to a wider spacing to direct widerbottles, in which case the outlet ends 148 of the combiner guides wouldnot be positioned over only three of the row conveyors but could bepositioned over all five of the row conveyors. The combiner guides 138receive bottles from the directional guides 136 at the inlet ends 146 ofthe combiner guides, and as the bottles are conveyed on the rowconveyors through the combiner guides 138 the bottles are arranged inside-by-side rows before they pass out of the combiner guides 138 attheir outlet ends 148.

Thus, with the transfer assembly described above, the accumulatedbottles conveyed by the conveyor system are transferred from theconveyor system through the transfer assembly and are arranged inside-by-side rows on three flex chain conveyors 118, 122, 124 thatfurther convey the rows of bottles to the bottle stop gate 10 and therow former 10.

With the split path conveyor system described above, each of thedownstream conveyors 22 can have their speeds adjusted up or downindependently of each other without affecting the speeds of theintermediate conveyors 18 or affecting the speeds of the row conveyors112, 114, 116, 118, 122, 124, 126. In addition, the interior five rowconveyors 114, 116, 118, 122, 124 can each have their speeds adjusted upor down independently of each other and independently of the two outermost row conveyors 112, 126.

FIG. 11 shows further modifications made to the upstream or infeedconveyor 16. FIG. 12 shows the position of the infeed conveyor shown inFIG. 11 relative to the remainder of the conveyor system shown in FIGS.3-6. The upstream conveyor 16 shown in FIG. 11 is basically the same asthat shown in FIG. 2 and described earlier. Like the upstream conveyorof FIG. 2, the upstream conveyor 16 of FIG. 11 selectively feeds aprocession of objects to the intermediate 18 and downstream 22conveyors. The upstream conveyor 16 has an inlet end 24 shown to theleft in FIG. 11 and an opposite outlet end 26 shown to the right in FIG.11. The conveyor is a belt or a chain conveyor having a top surface 28that conveys a procession of objects, in this illustrative exampleempty, blow molded plastic bottles, between the guide rails 32 of theconveyor. It includes the motive source 36 of the first describedembodiment of the upstream conveyor and provides a stream of bottles tothe diverter assembly 42. Like the upstream conveyor of FIG. 2, thediverter assembly 42 is basically the same and includes the divertergates 44 mounted on the diverter panels 46.

The upstream conveyor 16 shown in FIG. 11 differs from that of FIG. 2 inthat it includes a counter or encoder 160 and the infeed sensor 34 ofthe FIG. 2 embodiment of the conveyor is replaced by a modified sensor162. The modified sensor 162, the motive source 36, the diverterassembly 42 and the encoder 160 all communicate with the centralprocessing unit CPU 64 of the conveyor system.

FIG. 13 is a schematic representation of a typical photo sensorpositioned on opposite sides of a conveyor and the difficultiesencountered in determining an accurate gap between bottles conveyed pastthe photo sensors. Typically, the photo sensor 164 is comprised of asender 166 and a receiver 168 positioned on one side of the conveyor anda reflector 172 positioned on the opposite side of the conveyor. Thesender 166 would emit a signal 174 across the conveyor to sense bottlesB passing by the photo sensor and also to determine any gaps 176appearing between bottles. However, because the signal 174 sent acrossthe conveyor would diverge as it is sent across, it would lose some ofits intensity as it crossed the conveyor. In addition, the signal 174would further lose intensity as it passes through a narrow gap 176between adjacent bottles resulting in a weaker signal 178 beingtransmitted to the reflector 172. The reflected signal 182 would alsodiverge as it reflects back between the gap 176 of the bottles. Thereflected signal would further be weakened as it passes through the gap176, resulting in a significantly diluted signal 184 being received bythe receiver 168 of the photo sensor. Thus, with this prior artarrangement it was very difficult to obtain an accurate accounting ofgaps occurring between bottles conveyed along the conveyor system.Furthermore, this prior art system was incapable of sensing minute gapsbetween bottles.

A modified infeed sensor 162 of the invention employed on the upstreamconveyor shown in FIG. 11 overcomes the disadvantages of prior artsensors. As shown in FIG. 11 and in more detail in FIGS. 14 and 15, themodified infeed sensor 162 employs pairs of fiber optic photo electricsensors such as the D11 and D12 mini-beam “FP” series optic fibersensors provided by Banner Engineering Corp. of Minneapolis, Minn. Asshown in FIGS. 14 and 15, a first sender 186 and receptor 188 pair offiber optic photo sensors is positioned on opposite sides of theconveyor and a second sender 192 and receptor 194 pair of optic fiberphoto sensors is also positioned on opposite sides of the conveyor. Eachsender and receptor is actually a plurality of senders or receptorsarranged in a single vertical column. The sender 186 of the first pairis positioned adjacent the receptor 194 of the second pair and thesender 192 of the second pair is positioned adjacent the receptor 188 ofthe first pair. The pairs of senders and receptors are supported on abracket 196 that is attached to the frame (not shown) of the conveyorand positions the senders and receptors adjacent the top conveyingsurface 28 of the upstream conveyor 16. In this position of the sendersand receptors they are assured of sensing bottles that pass between thephoto sensors and are assured of accurately sensing gaps occurringbetween the bottles. Because bottles generally have contoured shapes asthey extend upwardly from their bottoms, positioning the senders andreceptors adjacent the belt surface 28 prevents inaccurate readings ofgaps between adjacent bottles where bottles could actually be inengagement with each other but because of their contoured shapes abovethe bottoms of the bottles, there may be a gap occurring between bottlesthat engage each other. In the arrangement shown the first sender 186sends signals from optic fibers arranged in a single vertical column asshown in FIG. 14 across the upstream conveyor 16 to the first receptor188. In a like manner the second sender 192 sends signals across theupstream conveyor 16 to the second receptor 194. A majority of thereceptors must receive light to register a gap. Because the signals arenot reflected back to a receptor as was done in the prior art, themodified infeed sensor 162 of the invention obtains a much more accuratedetermination of bottles passing between the infeed sensors and moreimportantly obtains a much more accurate count of gaps occurring betweenbottles.

The encoder 160 and the modified infeed sensor 162, and specifically thesender 186 and receptor 188 of the first pair of photo sensors and thesender 192 and receptor 194 of the second pair of photo sensorscommunicates with the central processing units 64 which alsocommunicates with the motive source 36, the diverter assembly 42 and thediverter assembly gates 44. The encoder 160 is also operativelyconnected to the upstream conveyor 16, for example by a belt and pulleyconnection, and sends pulsed signals to the central processing unit 64as the upstream conveyor is operated. The pulsed signals arerepresentative of the flight motion of the upstream conveyor 16.

In operation of the upstream conveyor in a bottle accumulating mode withthe diverter gates 44 closed, the conveyor speed is increased to quicklyaccumulate bottles on the conveyor behind the closed gate. As long asthe infeed sensor 162 is sensing light the conveyor 16 is continued tobe operated with the gates 44 closed accumulating bottles behind thegates on the upstream conveyor. As bottles are accumulated on theconveyor they pass through the light beams of sensors 162 blocking thelight and causing the sensor to sense a dark condition. During the darkperiods of sensor 162 the CPU collects and sums pulses from the encoder160. When a predetermined set of dark pulses is summed up by the CPU,the CPU knows that at least a number of bottles sufficient to reach backto the infeed sensor 162 have been accumulated on the upstream conveyorbehind the closed gates 44. As the conveyor continues to operate theencoder 160 continues to send signals to the CPU representative ofadditional bottles that are accumulated behind the bottle sensed by theinfeed sensor 162, whether these additional bottles are beingaccumulated or not. The counting by the CPU of the encoder pulsescontinues until it reaches a predetermined number of pulses thatrepresents the number of bottles needed to send bottles to thedownstream conveyor and to provide bottles behind the diverter gates 44to prevent bottles from falling over upon impact of the next sequentialcycle of closing the gates. When this predetermined number is reachedthe bottle accumulating speed of the upstream conveyor is reduced andthe diverter assembly 42 is directed to the intermediate or downstreamconveyor needing bottles and the gates 44 are opened. With the gatesopen the speed of the upstream conveyor is controlled to increase toquickly supply the bottles where needed. The number of bottles to besupplied are counted by the CPU as it receives signals from the bottlecounting sensor 48.

As the upstream conveyor 16 operates at its increased speed with thefirst diverter gates 44 open, when the infeed sensors 162 senses anygaps occurring between the procession of conveyed bottles by thereceptors 188, 194 of the sensor receiving the optical signals sent bythe senders 186, 192, the CPU monitors and sums up the gaps. In order tosense a gap the majority of receptors 188, 194 of each pair must senselight. When the gaps are sensed the pulses from the encoder 160 are sentto the CPU 64 that sums up the size of the gaps. In addition, the sensedgaps are summed by the CPU 64 for the procession of bottles beingconveyed by the upstream conveyor through the diverter gates 44. Anacceptable size gap or summed gaps is recorded in the CPU 64 fordifferent sizes or numbers of bottles in a procession of bottles sentthrough the diverter assembly 42. If the upstream conveyor runs out ofbottles the sensor will sense continuous light causing the predeterminedgap size to be reached very quickly. The sum of the gaps sensed iscompared to the acceptable predetermined gap size to insure that thesummed gap does not become too large as to present the potential problemof there being an insufficient number of bottles accumulated behind thegates 44 when the gates are closed to act as a cushion for the remainingbottles accumulated before the gates and later arriving bottles thatcushions their impact with the accumulated bottles and prevents theirfalling over. If the predetermined total gap recorded in the CPU isreached by the gaps sensed by the sensors and summed by the CPU, the CPUwill control the upstream conveyor to reduce speed and the upstreamconveyor 16 will continue to operate at the reduced speed while anadditional set of predetermined encoder pulse counts is reached, whichalso prerecorded in the CPU 64, as bottles are conveyed past themodified infeed sensor 162. This secondary encoder pulse count createsan opportunity for the conveyed bottles at reduced speed to reduce theirgapping. If the gapping reduces to tolerable levels, the CPU will allowthe conveyor 16 to resume its high speed. However, if the summed gapsize continues to increase due to additional or continued gaps betweenthe bottles conveyed at the lower speed such that the summed additionalgap reaches the secondary predetermined encoder pulse count, then theCPU 64 will automatically control the gates 44 of the diverter assembly42 to close, thereby ensuring that a sufficient number of bottles willremain on the upstream conveyor accumulated behind the diverter gates 44to act as a cushion to absorb impacts of the remaining bottles on theconveyor before the gates and the later arriving bottles and preventingtheir falling over. With the gates 44 closed the upstream conveyor speedis increased and the procession of bottles is again allowed to quicklyaccumulate on the upstream conveyor and the above described process isrepeated.

The alternate embodiment of the upstream conveyor 16 of the inventionshown in FIG. 11 also employs a vacuum system 202. Vacuum systems areknown in the prior art and therefore the system shown in FIG. 11 willonly be described generally. The vacuum system 202 is basicallycomprised of three hollow vacuum housings 204 that are communicated witheach other through vacuum pressure equalizing conduits 206. Mounted totwo of the housings 204 adjacent the conveyor inlet end 24 and outletend 26 are blowers 208 and blower motors 212. Operation of the blowermotors 212 is controlled by the CPU 64. On operation of the blowermotors 212 vacuums are created in the vacuum housings 204 and the vacuumpressure is equalized between the three housings by the vacuum conduit206. Each of the vacuum housings communicates with the interior of avacuum plenum 214 directly beneath the conveyor top surface 28 and shownin cross section in FIG. 14. A plurality of holes (not shown) passthrough the belt surface 28 to the interior of the vacuum plenum 214communicating the vacuum pressure in the plenum to the belt surface 28.This vacuum pressure holds bottles conveyed on the belt surface 28 tothe belt surface and prevents bottles from falling over when impacted byother bottles or when conveyed at increased speeds or abruptly changingspeeds.

Recent developments in plastic bottle constructions have enabled theirconstructions with thinner plastic walls. The thinner walls result inthe bottles being compressed more when conveyed by the upstream conveyor16 and held back by the gates 44 of the diverter assembly. In addition,the increased speeds of the upstream conveyor 16 also contribute to theincreased pressure exerted on the bottles held back by the divertergates 44. Still further, when the vacuum system 202 is operated holdingthe bottles to the belt top surface 28 it further increases the pressureexerted on a stream or procession of bottles held back by the divertergates 44. As explained earlier, this increased pressure could result inone or more bottles springing through the gates 44 ahead of theprocession of bottles as the gates are opened resulting in the one ortwo bottles falling over onto one of the intermediate or upstreamconveyors 18 as the gates are opened.

The upstream conveyor 16 of the invention shown in FIG. 11 is modifiedto overcome this problem. Firstly, the central processing unit 64 isprogrammed so that just prior to the opening of the diverter gates 44,the motive source 36 of the upstream conveyor 16 is controlled todecrease its speed, thereby reducing the pressure exerted on theprocession of bottles held back by the gates 44. This reduced pressurein the accumulated bottles of the procession reduces the likelihood ofone or two bottles springing forward as the gates are opened. Stillfurther, if the upstream conveyor 16 is operated with the vacuum system202 disclosed, the central processing unit 64 is programmed so that thevacuum pressure created by the vacuum system 202 is decreased just priorto the gates 44 of the diverter assembly 42 being opened. The decreasein vacuum pressure further reduces the pressure exerted on the bottlesaccumulated behind the gates and therefore further reduces thelikelihood of one or two bottles springing forward as the gates areopened. Although it is possible to both decrease speed and vacuumpressure, it is not necessary that the motive source 36 and vacuumsystem 202 be operated by the CPU 64 to both decrease their respectivespeeds and vacuum pressures just prior to the diverter assembly gates 44opening, however this provides the greatest decrease in pressure exertedon the accumulated bottles. In alternative embodiments, the CPU 64 couldcontrol the motive source 36 alone to decrease its speed and therebydecrease the pressure exerted on a procession of bottles accumulatedbefore the diverter gates 44, or the vacuum source 202 could becontrolled by the CPU 64 alone to reduce the pressure exerted on aprocession of bottles accumulated behind the gates 44.

Although only the upstream conveyor 16 has been described as includingthe improvements of the infeed sensor controls and the vacuum controls,these improvements could also be employed on the other conveyors.

A further improvement to the conveyor system of the invention is shownin FIG. 16. FIG. 16 shows modified downstream conveyors that employ manyof the component parts of the earlier described conveyor system andtherefore these component parts are identified by the same referencenumerals employed earlier followed by a prime (′). The downstreamconveyors 22′ of FIG. 16 differ primarily from the earlier describeddownstream conveyors 22 shown in FIGS. 4, 5 and 6 in that the downstreamconveyors 22′ of FIG. 16 are six in number instead of the previouslydescribed four conveyors. In addition, the downstream conveyors 22′ arefed by a second diverter 66′ and a third diverter 68′ that divert flowsof objects, in this case plastic bottles, to three of the downstreamconveyors each. The first through sixth of the downstream conveyors areidentified by the letters A through F in FIG. 16. The second diverter66′ selectively channels or directs a flow of bottles to the first threeof the downstream conveyors A, B and C and the third diverter 68′directs a flow of bottles to the second three conveyors D, E and F. Fromthe downstream conveyors A-F, the flow of bottles are conveyed throughthe transfer assembly outlet lanes 106′ and around a turn in theconveyor system to the end of the row former 12′ that feeds rows of thebottles conveyed to the row former to a palletizer that arranges thebottles in two dimensional arrays on a pallet.

With the downstream conveyors 22′ feeding six rows of bottles to the rowformer 12′, the row former can move six rows of bottles, each row havingthe same number of bottles, to the palletizer at a time. However,pallets come in many different sizes and the conveyor system of theinvention is designed to convey objects or bottles of different sizes.Therefore, it may be necessary to arrange two dimensional arrays ofbottles having different sizes onto pallets of different sizes. Forexample, it may be necessary to arrange an array of nineteen rows ofbottles onto a pallet. To accomplish this, the bottle stop gates 10′ ofeach of the rows or lanes are operated together to sequentially providethree groups of six rows of bottles to the row former 12 with each rowhaving the same number of bottles, and then only one of the bottle stopgates 10 is operated to cause a single row of the number bottles to besupplied to the row former 12, thereby providing the total of nineteenrows of bottles to be formed up by the row former 12′ and delivered tothe palletizer to be put on a pallet. However, this presents a problemin that one of the six rows A-F of the downstream conveyors will notonly have bottles taken from it in forming the first three groups of sixrows of bottles, but will have an additional row of bottles taken fromit in forming the nineteenth row to be swept onto the pallet. Thus, thislane will be depleted of bottles quicker than the other lanes of thedownstream conveyor. Row former photosensors 218 are provided onopposite sides of the outlet lanes 106′ to ensure that enough bottlesare accumulated in the lanes for the row former 12′ to form an array ofbottles to be swept on a pallet, but if one of the sensors 218 detectthe absence of bottles, the diverters 66′, 68′ may not operate quickenough to supply bottles to the depleted row and the operation of thepalletizer 12′ may be held up until enough bottles are available in allof the outlet lanes or rows 106′, thus decreasing the time efficiency ofthe conveyor system, in particular the palletizer.

To address this problem, the central processing unit 64 controls thebottle stop gates 10′ so that each time a single row of bottles isneeded to complete an array, for example nineteen rows of bottles beingswept onto a pallet, the stop gates alternate in taking the nineteenthrow or single row of bottles from one of the three rows A, B, C fed bythe second diverter 66′ and one of the three rows D, E, F fed by thethird diverter 68′. In the preferred embodiment, the stop gates 10′ arecontrolled so that they alternate in supplying the single row of bottlesto complete an array of bottles from the row A fed by the seconddiverter 66′ and the row D fed by the third diverter 68′. With thepalletizer moving rows of bottles to the right as viewed in FIG. 16 whenforming arrays of bottles to be swept onto a pallet, rows A and D arethe two rows fed by the two different diverters that feed single rows ofbottles to positions closest to the array of bottles being formed,thereby saving time at the row former 12′ in pushing the single row ofbottles across the row former to the array of bottles being formed to bepalletized. Thus, by alternating between one row A fed by the seconddiverter 66′ and one row D fed by the third diverter 68, the effect ofdepleting the supply of bottles accumulated in one row of the downstreamconveyor faster than the other rows of the downstream conveyor isminimized.

Although the example described above refers to forming a nineteen rowarray of bottles to be palletized, other arrangements of controlling thestop gate's 10′ and the diverters 66′, 68′ could be used in formingdifferent arrays of bottles. For example, in forming a nine row array ofbottles, all of the stop gates 10′ would be opened to form the first sixrows and then it would only be necessary to open three more of the stopgates to provide the final three rows of bottles in forming a nine rowarray. In this situation, the central processing unit 64 would controlthe individual stop gates 10′ of one row fed by the second diverter 66′and two of the rows fed by the third diverter 68′ to provide theadditional three rows of bottles in forming the nine row array, and thenalternate by opening the stop gates of two of the rows fed by the seconddiverter 66′ and one of the rows fed by the third diverter 68′ inproviding the additional three rows when the next nine row array ofbottles is formed.

Furthermore, because it is known that certain conveyor rows will berelied on in supplying additional rows of bottles when forming a twodimensional array of bottles to be palletized, the central processingunit CPU can be controlled to provide an extra number of bottles to therows from which the extra bottles are taken in forming the arrays ofbottles at the palletizer. In the example described above, where rows Aand D of the multilane conveyor provide additional single rows ofbottles to the palletizer, the central processing unit 64 controls thediverter to supply an extra number of bottles, for example 22 bottles,alternately to rows A and D to ensure that these rows do not run out ofbottles when supplying the extra rows of bottles to the palletizer. TheCPU 64 controlling the operation of the conveyor system also monitorsthe operation of the palletizer and has prior knowledge of when anadditional row of bottles is taken from rows A or D by the palletizer.For example, when the palletizer takes an additional row of bottles fromconveyor row D in forming a two dimensional array of bottles, the CPUhas prior knowledge that the next additional row of bottles will betaken from conveyor row A. With this prior knowledge, the CPU can thencontrol the diverter to provide an extra number of bottles to row A thenext time the diverter is controlled to supply a number of bottles torow A. For example, if the sensors of row A cause the CPU to control thediverter to direct a large number of bottles to row A, an additionalnumber of bottles will be added to the large number of bottles in orderto ensure that there are sufficient bottles supplied to row A to preventthe number of bottles in row A being depleted by the palletizer takingan additional row of bottles from row A in forming a two dimensionalarray of bottles. This process is repeated in supplying bottles to rowD, the other row from which additional rows of bottles are taken by thepalletizer in forming two dimensional arrays of bottles. The CPU willcontrol the diverter in supplying an extra number of bottles to eitherrows A or D in response to the sensor signals of the respective rowsreceived by the CPU, provided that there is room on the particularconveyor row to receive the extra number of bottles.

To further ensure that each of the six conveyor lanes or rows A-F of thedownstream conveyor of FIG. 16 are filled with accumulated bottles asthey are fed to the stop gates 10′ and the row former 12′, thedownstream conveyor 22′ of FIG. 16 includes the additional modificationof early warning photosensors 220 positioned on opposite sides of eachof the downstream conveyor lanes A-F just prior to the outlet lanes 106′of the transfer assembly. The early warning photosensors 220 communicatewith the CPU 64 in the same manner as the low photosensor 92′, the fullphotosensor 94′ and the midway photosensor 96′ of the downstreamconveyors described earlier. When the early warning photosensors 220detect the absence of bottles at their positions adjacent the downstreamconveyors A-F (and the other three sensors 92′, 94′, 96′ also detect theabsence of bottles), they provide a signal to the central processingunit 64 which in turn controls each of the second 66′ and third 68′diverters to supply an extra large number of bottles to fill theconveyor lane of the early warning photosensor 220 detecting the absenceof bottles.

In addition, in a similar manner to the earlier described automaticconversion, if the early warning sensor 220 detects bottles in a lane,but the low photosensor 92′, the midway photosensor 96′ and the fullsensor 94′ sense the absence of bottles in the land and the CPU controlsthe gates of the diverter assembly to open and supply a number ofbottles to the downstream conveyor lane to fill the space between thelow sensor 92′ and the diverter, and then the early warning photosensor220 along the conveyor lane opens indicating that the last of thebottles previously accumulated on the conveyor lane has passed the earlywarning photosensor 220, the early warning sensor signal sent to thecentral processing unit 64 will cause it to reset the CPU counter tochange between the number of bottles that will fill the space betweenthe low sensor 92′ and the diverter assembly, to include an additionalnumber of bottles so that the total number of bottles supplied by thediverter will fill the space between the early warning photosensor 220and the diverter. This makes use of the entire length of the conveyorlanes in accumulating bottles before the row former 12′. In addition, byconverting the number of bottles being counted by the CPU from a smallernumber to a larger number as the bottles are being counted and directedto the conveyor lane, a switch of the diverter and its loss of conveyingtime are eliminated and more uninterrupted conveying time is gained,thus improving time efficiency of the conveyor system.

In addition to providing early warning photosensors 220 for each of thedownstream conveyors 22′, it should be apparent that additional fourthphotosensors 222 could also be positioned along the intermediateconveyors 52, 54 at positions just prior to the transfer from the inletsections 18 a to the outlet sections 18 b as shown in FIG. 3. This willprovide four photosensors 56, 58, 62, 222 along the lengths of theintermediate conveyor inlet sections to control the numbers of bottlessupplied to the intermediate conveyors by the first diverter assembly42. The operation of the additional fourth photosensors 222 enables theCPU 64 to control the gates of the first diverter assembly 42 to nowprovide four different numbers of bottles to the intermediate conveyorsdepending on the signals received from the photosensors by the CPU. Withall the photosensors 56, 58, 62, 222 being opened, thereby sensing nobottles on the inlet section 18 a of an intermediate conveyor, the CPUcontrols the gates of the first diverter assembly 42 to open and supplyan extra-large number of bottles to the conveyor to fill the conveyorbetween the additional fourth photosensors 222 and the first diverter42. In a like manner, if the fourth photosensor 222 is closed sensing apresence of bottles by the sensor, and the other three sensors, the lowsensor 56, the midway sensor 62 and the full sensor 58 are open sensingthe absence of bottles, the CPU 64 is controlled to supply a largenumber of bottles to the conveyor to fill the conveyor between the lowsensor 56 and the first diverter assembly 42. If during the time thenumber of bottles being supplied to the conveyor the fourth sensor 222then opens sensing the absence of bottles at its position, the CPU 64then converts the number of bottles being supplied to an extra largenumber and controls the first diverter assembly 42 to supply the extralarge number of bottles to fill the conveyor between the fourth sensor222 and the diverter as explained earlier. In this manner, the additionof an additional fourth photosensor 222 along the inlet sections 18 a ofthe intermediate conveyors makes full use of the lengths of theconveyors between their fourth sensors and the diverter in accumulatingbottles as such lengths of the conveyors become simultaneouslyavailable.

The conveyor system of the present invention has also been improved inthe method in which it controls the operation of the diverters insupplying numbers of bottles to each of the conveyor lanes downstream ofthe diverters. For example, it had been discovered in operation of theconveyor systems of the parent applications that when the first diverterassembly 42 was supplying numbers of bottles to the two intermediateconveyors 18, or the second 66 or third 68 diverter assemblies weresupplying bottles to each of the three downstream conveyors 22′ fed bythe diverters, the central processing unit 64 would control the diverterassemblies to supply the number of bottles available to it to a conveyorlane on an as needed basis until that number of bottles available to thediverter ran out. For example, in the six lane downstream conveyor 22′shown in FIG. 16, the second diverter assembly 66′ would be controlledby the CPU 64 to supply a set number of bottles available to itaccumulated upstream of the diverter assembly to each of the downstreamconveyor lanes A, B, C, on an as needed basis as indicated by thephotosensors 92′, 94′, 96′, 220 of each lane until the number of bottlesavailable to the diverter ran out. This could result in a situationwhere conveyor lane A would be supplied with all the bottles needed tofill the lane, conveyor lane B would be supplied with all the bottlesneeded to fill the lane, but conveyor lane C would be supplied with alesser number of bottles needed to fill the lane because the number ofbottles available to the second diverter 66′ ran out. It is noted thatthis situation, or a similar situation involving the other lanes, wouldrepeat itself, resulting in one of the three conveyor lanes suppliedwith bottles by the diverter assembly always having a low number ofbottles accumulated on the conveyor lane.

To overcome this problem, the present invention devised a method ofcontrolling the supply of bottles to the three conveyor lanes downstreamfrom a diverter assembly to insure that one of the lanes does notrepeatedly have a low number of bottles accumulated on the lane. In theexample of the second diverter assembly 66′ and the three downstreamconveyor lanes A, B, C fed by the diverter assembly, the CPU 64 wouldcontrol the diverter 66′ to supply bottles to each of the three lanes asneeded until the bottles ran out. In a situation where conveyor lane Aand conveyor land B were provided with all of the bottles they needed tofill the lanes, but conveyor lane C was provided with the remainingavailable bottles until the bottles ran out, the second diverterassembly 66′ would be controlled to remain at conveyor lane C until anadditional number of bottles becomes available to the diverter assemblyso that the number of bottles being supplied to conveyor lane C beforethe bottles ran out could be completed. Thus, for example, if conveyorlane C required an extra large number of bottles with all of itsphotosensors 92′, 94′, 96′, 220 being open, and the second diverterassembly 66′ began supplying a number of bottles sufficient to fill theconveyor lane but the supply of bottles to the diverter assembly runsout before the lane is filled, for example only supplying thirty bottlesto lane C where sixty bottles are needed to fill the lane, the CPU 64would control the diverter assembly 66′ to remain at conveyor lane Cuntil additional bottles are made available to the second diverterassembly 66′. The CPU will then control the gates of the diverterassembly to open and supply the missing thirty bottles to conveyor laneC, overriding the sensors 92, 94, 96 or 222 of lane C that may becomeblocked, because of the prior knowledge that there was room on conveyorlane C for the previously determined number of bottles. The CPU thenwould control the diverter to switch to provide bottles to either ofconveyor lanes A or B as needed. In this manner, the problem of one ofthe lanes fed by a diverter assembly being repeatedly low on the numberof bottles accumulated in the lane is eliminated.

While the present invention has been described by a reference to aspecific embodiment, it should be understood that modifications andvariations of the invention may be constructed without departing fromthe scope of the invention defined in the following claims.

What is claimed:
 1. A method of improving time efficiency of a conveyed path splitting conveyor system comprising: providing an upstream conveyor and first and second downstream conveyors; positioning a diverter between the upstream conveyor and the first and second downstream conveyors where the diverter is operable to selectively direct a procession of objects conveyed on the upstream conveyor to one of the first and second downstream conveyors; spacially arranging a first plurality of sensors along the first downstream conveyor with each of the first plurality of sensors being operable to sense a presence or an absence of an object conveyed by the first downstream conveyor at a location along the first downstream conveyor and to emit a signal indicative of the sensed presence or absence of the object; spacially arranging a second plurality of sensors along the second downstream conveyor with each of the second plurality of sensors being operable to sense a presence or an absence of an object conveyed by the second downstream conveyor at a location along the second downstream conveyor and to emit a signal indicative of the sensed presence or absence of the object; and causing the diverter to direct objects to the first downstream conveyor in response to at least one of the first plurality of sensors sensing the absence of an object and controlling the diverter to direct objects to the second downstream conveyor in response to at least one of the second plurality of sensors sensing the absence of an object.
 2. The method of claim 1, further comprising: causing the diverter to direct different numbers of objects to the first downstream conveyor in response to different sensors of the first plurality of sensors sensing the absence of an object and causing the diverter to direct different numbers of objects to the second downstream conveyor in response to different sensors of the second plurality of sensors sensing the absence of objects.
 3. The method of claim 1, further comprising: causing the diverter to direct a number of objects to the first downstream conveyor in lieu of the second downstream conveyor in response to a number of the first plurality of sensors sensing the absence of an object being greater than a number of the second plurality of sensors sensing an absence of an object.
 4. The method of claim 3, further comprising: causing the diverter to direct a number of objects to the second downstream conveyor in lieu of the first downstream conveyor in response to a number of the second plurality of sensors sensing the absence of an object being greater than a number of the first plurality of sensors sensing an absence of an object.
 5. The method of claim 1, further comprising: causing the diverter to direct a number of objects to the first downstream conveyor in response to a number of the first plurality of sensors sensing the absence of an object and then increasing the number of objects while they are directed to the first downstream conveyor in response to an additional sensor of the first plurality of sensors sensing an absence of an object.
 6. The method of claim 5, further comprising: causing the diverter to direct a number of objects to the second downstream conveyor in response to a number of the second plurality of sensors sensing the absence of an object and then increasing the number of objects while they are directed to the second downstream conveyor in response to an additional sensor of the second plurality of sensors sensing an absence of an object.
 7. The method of claim 5, further comprising: causing the diverter to continue to direct the number of objects to the first downstream conveyor until all of the number of objects have been directed to the first downstream conveyor.
 8. The method of claim 7, further comprising: causing the diverter to continue to direct the number of objects to the second downstream conveyor until all of the number of objects have been directed to the second downstream conveyor.
 9. The method of claim 1, further comprising: providing a third downstream conveyor; positioning the diverter between the upstream conveyor and the third downstream conveyor where the diverter is operable to selectively direct a procession of objects conveyed on the upstream conveyor to one of the first, second and third downstream conveyors; spacially arranging a third plurality of sensors along the third downstream conveyor with each of the third plurality of sensors being operable to sense a presence or an absence of an object conveyed by the third downstream conveyor at a location along the third downstream conveyor and to emit a signal indicative of the sensed presence or absence of the object; and, causing the diverter to direct objects to the third downstream conveyor in response to at least one of the third plurality of sensors sensing the absence of an object.
 10. The method of claim 9, further comprising: causing the diverter to direct a number of objects to the third downstream conveyor in lieu of the first downstream conveyor and the second downstream conveyor in response to a number of the third plurality of sensors sensing an absence of an object being greater than a number of the first plurality of sensors sensing an absence of an object and being greater than a number of the second plurality of sensors sensing an absence of an object.
 11. The method of claim 9, further comprising: causing the diverter to direct a number of objects to the third downstream conveyor in response to a number of the third plurality of sensors sensing the absence of an object and then increasing the number of objects while they are directed to the third downstream conveyor in response to an additional sensor of the third plurality of sensors sensing an absence of an object.
 12. The method of claim 1, further comprising: providing the first downstream conveyor with a length having opposite inlet and outlet ends and positioning the inlet end adjacent the diverter; and providing the first plurality of sensors with at least three sensors that are spatially arranged along the length of the first downstream conveyor including a low sensor that is positioned adjacent the outlet end of the first downstream conveyor, a full sensor that is positioned adjacent the inlet end of the first downstream conveyor and an intermediate sensor that is positioned adjacent the first downstream conveyor between the low sensor and the full sensor.
 13. The method of claim 12, further comprising: providing the second downstream conveyor with a length having opposite inlet and outlet ends and positioning the inlet end of the second downstream conveyor adjacent the diverter; and providing the second plurality of sensors with at least three sensors that are spatially arranged along the length of the second downstream conveyor including a low sensor positioned adjacent the outlet end of the second downstream conveyor, a full sensor positioned adjacent the inlet end of the second downstream conveyor and an intermediate sensor positioned adjacent the second downstream conveyor between the low sensor and full sensor.
 14. The method of claim 13, further comprising: positioning the full sensor and the intermediate sensor of the first downstream conveyor at a greater distance apart than the intermediate sensor and the low sensor; and positioning the full sensor and the intermediate sensor of the second downstream conveyor at a greater distance apart than the intermediate sensor and the low sensor of the second downstream conveyor.
 15. A method of improving the time efficiency of a conveyed path splitting conveyor system comprising: providing an upstream conveyor and first and second downstream conveyors; positioning a diverter with a hold back gate between the upstream conveyor and the first and second downstream conveyors where the diverter gate is operable to hold back objects conveyed on the upstream conveyor and open to selectively direct a procession of objects conveyed on the upstream conveyor to one of the first and second downstream conveyors; positioning a sensor along the upstream conveyor with the sensor being operable to sense a presence or an absence of an object conveyed by the upstream conveyor at a location along the upstream conveyor and to emit a signal indicative of the sensed presence or absence of the object; and, causing the diverter to selectively open the diverter gate and direct objects to one of the first downstream conveyor and the second downstream conveyor in response to the sensor emitting a signal indicative of the sensed presence of an object at the location along the upstream conveyor.
 16. The method of claim 15, further comprising: preventing the diverter gate from selectively directing objects to one of the first and second downstream conveyors in response to the sensor emitting a signal indicative of the sensed absence of an object at the location along the upstream conveyor.
 17. The method of claim 15, further comprising: positioning the sensor along the upstream conveyor at a distance along the upstream conveyor from the diverter where a plurality of objects can accumulate on the upstream conveyor between the diverter gate and the sensor where the plurality of objects act as a cushion that absorbs impacts of other objects conveyed on the upstream conveyor that impact with the plurality of objects.
 18. The method of claim 15, further comprising: providing the sensor as a first sender and first receptor pair positioned above the upstream conveyor on opposite sides of the upstream conveyor and as a second sender and second receptor pair positioned above the upstream conveyor and on opposite sides of the upstream conveyor.
 19. The method of claim 18, further comprising: positioning the first sender adjacent the second receptor on one side of the upstream conveyor and positioning the second sender adjacent the first receptor on the opposite side of the upstream conveyor.
 20. The method of claim 19, further comprising: providing the first sender and the first receptor as pluralities of optic fiber photo sensors and providing the second sender and the second receptor as pluralities of optic fiber photo sensors. 